Bennett Mechanical Test Bennett Mechanical Friction and Inclined Planes Questions and Answers 2

Question 1

If the angle of an inclined plane increases, what happens to the force needed to push an object up it?

Accepted Answer

It increases

Answer

A steeper angle increases the parallel gravity component, so more force is needed to push the object upward.

Question 2

A wedge is a type of simple machine based on which underlying principle?

Accepted Answer

Inclined plane

Answer

A wedge is essentially two inclined planes joined back-to-back, using the same mechanical advantage principle.

Question 3

Which factor does NOT affect the magnitude of the kinetic friction force between two surfaces?

Accepted Answer

Area of contact

Answer

For most surfaces, friction force depends on normal force and the coefficient of friction, not on contact area.

Question 4

A 50 kg crate rests on a 30° incline (g = 10 m/s²). What is the normal force the incline exerts on the crate?

Accepted Answer

433 N

Answer

Normal force = mg cos30° = 500 × 0.866 ≈ 433 N.

Question 5

Static friction compared to kinetic friction for the same pair of surfaces is always:

Accepted Answer

Greater than or equal to kinetic friction

Answer

It takes more force to start an object moving than to keep it moving, so static friction ≥ kinetic friction.

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